^3rd Degree of Relation: 12.5% Genes Shares, Approximately 3,750 genes in common (30,000 genes total). Now, Granduncle Kenny and Greatniece Fiona are genetically similar the same as: First cousins, great grandparents, great grandchildren, great aunts, great uncles, grandnieces, grandnephews, half-aunts, half-uncles, half-nephews, half-neices.^